The present disclosure relates to an energy system.
An energy storage system is a system that stores produced power in various associated systems including a power station, a substation and a transmission line and then uses the stored power selectively, efficiently as needed to enhance energy efficiency.
When an electrical load having a significant change according to a time zone and season is leveled to enhance the overall load factor, the energy storage system may reduce a power cost, save an investment cost and operation cost required for increasing a power facility, and so it is possible to reduce electric charges and save energy.
Such an energy storage system is being installed in a power station, a power transmission and distribution station, and home in the electrical system and performs functions, such as frequency regulation, generator output stabilization using new renewable energy, peak shaving, load leveling, a emergency power source.
The energy storage system is roughly divided into physical energy storage and chemical energy storage according to a storage method. The physical energy storage uses pumping-up power generation, compressed air storage, flywheel, etc. and the chemical energy storage uses a lithium ion battery, a lead storage battery, a Nas battery, etc.
The energy storage system also performs scheduling operations of using the stored energy in a time zone in which a power price is expensive and of storing energy in a time zone in which the power price is cheap, in association with power price bidding in a power market. It has an advantage in that it is possible to reduce a power usage cost by using the fact that the power price varies according to an amount of power generation and an amount of power usage.
Since the scheduling operations of the energy storage system using the power price only enable a desired control value to be maintained by using a power price according to a time zone, they fail to use a deadband for the desired control value according to the adjustment rule of a power market. Thus, the energy storage system repeats an operation in order to maintain the desired control value and due to the repeated operation, there is a limitation in that it fails to efficiently operate. Also, since the energy storage system fails to use an error range according to the adjustment rule of the power market, there is a limitation in that a battery control operation is unnecessarily repeated.
Thus, there is a need for a control device and control method that may operate the energy storage system within the deadband, an allowable range of the desired control value.